Keppra (Levetiracetam) for Dogs and Cats

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-09-20

Keppra is the brand name for levetiracetam, an anticonvulsant medication that veterinarians prescribe to dogs and cats with seizures. In small animal practice it is used most often as an add-on drug for pets that are already taking phenobarbital, potassium bromide, or another antiseizure medication and still having seizures [1][2][3]. It is also used on its own in some patients, and the injectable form is used in hospitals for cluster seizures and status epilepticus, a seizure that does not stop on its own [3]. Levetiracetam has a mechanism of action that differs from older antiseizure drugs, a favorable safety profile, and very little metabolism by the liver [3]. It is cleared by the kidneys, which matters for pets with kidney disease [4].

This article is educational and is not a substitute for veterinary diagnosis or treatment.

At a Glance

What Keppra Is and What It Treats

Levetiracetam is an antiseizure drug. In dogs it is used to reduce the frequency and severity of epileptic seizures, including in dogs whose seizures are not controlled by standard treatment [1][3]. In cats it has documented use in a specific seizure syndrome called feline audiogenic reflex seizures, where myoclonic seizures are triggered by certain sounds [7][8].

The drug has three main jobs in veterinary medicine.

The first is add-on therapy. Many dogs with epilepsy continue to have seizures on phenobarbital or potassium bromide. Adding levetiracetam can reduce seizure frequency without adding significant liver burden [1][2][3]. In one retrospective study of 52 dogs at a UK referral hospital, levetiracetam treatment produced a 50 percent or greater reduction in seizure frequency in 69 percent of dogs, and 15 percent of the dogs became completely seizure free [1].

The second is pulse or interval therapy for cluster seizures. Some dogs seize in clusters, meaning several seizures within a short period. In these dogs, levetiracetam can be given for a few days around the cluster rather than every day [1]. This approach is common in referral practice and is one of the reasons the drug is popular.

The third is emergency use. The injectable form is used in hospitals for status epilepticus and for cluster seizures that will not stop [3]. Levetiracetam is also being studied in an intranasal form for rapid seizure control in dogs, and a single-dose study in healthy dogs found that intranasal levetiracetam reached target blood concentrations within about 20 minutes and maintained them for roughly six to seven hours [9].

Levetiracetam does not treat the underlying cause of seizures. If a dog has a brain tumor, an infection, or a metabolic problem causing seizures, levetiracetam may reduce the seizures but will not fix the cause. That is why a full diagnostic workup matters before or alongside starting any anticonvulsant.

How Levetiracetam Works

Most older antiseizure drugs work by blocking sodium channels or enhancing GABA, the brain's main inhibitory signal. Levetiracetam works differently. It binds to a protein called SV2A, which is involved in how nerve cells release their chemical messengers [3]. This binding is the reason levetiracetam can work in patients who have not responded to other drugs, and it is also the reason it does not share the same side effect profile as phenobarbital.

The SV2A mechanism has practical consequences. Levetiracetam does not require the liver's cytochrome P450 enzyme system to be broken down, so it does not compete with many other drugs and does not put the same stress on the liver that phenobarbital does [3]. It is eliminated largely unchanged by the kidneys.

Levetiracetam also has linear kinetics, which means that if you double the dose, the blood level roughly doubles [3]. This makes it more predictable than some older drugs. Oral bioavailability is excellent, and the drug has minimal drug-drug interactions [3].

One interaction does matter. Phenobarbital, a common first-line anticonvulsant in dogs, increases the clearance of levetiracetam. In healthy dogs, concurrent phenobarbital reduced levetiracetam peak concentration by roughly half and shortened its elimination half-life from about 3.4 hours to about 1.7 hours [10]. A later study in dogs with epilepsy confirmed that phenobarbital lowers serum levetiracetam concentrations in a dose-dependent way [11]. This is why dogs on phenobarbital often need higher levetiracetam doses or more frequent dosing than dogs on levetiracetam alone.

Potassium bromide does not have the same effect. In dogs taking levetiracetam with bromide, peak levetiracetam concentrations and total drug exposure were significantly higher than in dogs taking levetiracetam with phenobarbital [2]. This is another reason dosing has to be individualized.

Labeled Uses and Real-World Use in Dogs and Cats

Levetiracetam is not FDA-approved as a veterinary drug for dogs or cats. It is a human medication that veterinarians prescribe off-label, which is legal and common in veterinary practice. The drug is available as Keppra, Keppra XR, and several generic products, and it is also compounded into liquid form for pets that cannot take tablets [5].

In dogs, the published uses include:

• Add-on therapy for drug-resistant idiopathic epilepsy, especially in dogs with cluster seizures [12][1].
• Monotherapy in some dogs with idiopathic epilepsy, though evidence for monotherapy is mixed [13][14].
• Monotherapy in dogs with structural epilepsy, meaning seizures caused by an identifiable brain lesion. In one case series of 19 dogs, 10 had a good response and 7 became completely seizure free, and the percentage of dogs experiencing cluster seizures dropped from about 68 percent to about 16 percent [15].
• Treatment of suspected myoclonic seizures. In a small case series of five dogs, two became seizure free for at least a year and two had a marked reduction in seizure frequency [16].
• Pulse therapy for cluster seizures [1].

In cats, the strongest evidence is for feline audiogenic reflex seizures. In a randomized controlled trial of 57 cats, a 50 percent or greater reduction in myoclonic seizure days occurred in 100 percent of cats on levetiracetam compared with 3 percent on phenobarbital, and 50 percent of levetiracetam-treated cats became free of myoclonic seizures during the treatment period compared with none on phenobarbital [7]. This syndrome typically starts late in life, with a median onset around 15 years, and is strongly represented in Birmans [8].

What Levetiracetam Does Not Cover

Levetiracetam is not a cure for epilepsy. It reduces seizure frequency in many patients but does not eliminate seizures in all of them. In the 52-dog retrospective study, 15 percent became seizure free, which means 85 percent did not [1]. Treatment failure rates in a separate study of dogs on monotherapy were 35 percent for levetiracetam, 45 percent for zonisamide, and 51 percent for phenobarbital, with failure most often due to inadequate seizure control [14].

Levetiracetam also does not replace a diagnostic workup. Seizures in dogs and cats can be caused by structural brain disease, metabolic disease, toxins, or idiopathic epilepsy. The drug treats the seizure, not the cause.

Levetiracetam is not a first-choice drug for every seizure patient. Phenobarbital remains the most commonly prescribed first-line antiseizure drug in dogs in primary care [17][18]. Levetiracetam is often chosen as an add-on or when liver concerns make phenobarbital less attractive.

How Keppra Is Given

Levetiracetam is given by mouth as tablets, chewable tablets, or compounded liquid. It can also be given intravenously in a hospital setting [3][5]. An extended-release oral formulation exists and is used in dogs. In one large primary care study, extended-release levetiracetam was used in 97.4 percent of dogs prescribed the drug, with a median dose of 29.7 mg/kg by mouth [17].

The extended-release form has practical advantages. A pharmacokinetic study in healthy dogs found that a single 30 mg/kg oral dose of extended-release levetiracetam kept serum concentrations above 5 micrograms per milliliter for approximately 20 hours, whether the dog was fed or fasted [6]. Food slightly delayed the time to peak concentration and slightly increased total absorption, but the difference was not large enough to require dosing on an empty stomach [6].

Levetiracetam is short-acting compared with phenobarbital. Many dogs need dosing two or three times daily, and some need three times daily when on phenobarbital because phenobarbital speeds up levetiracetam clearance [10]. The extended-release form allows twice-daily dosing in many dogs [6].

In cats, the published protocol for audiogenic reflex seizures used levetiracetam at 20 to 25 mg/kg every 8 hours [7]. This is a named protocol from a controlled trial and is the dose a veterinarian would reference.

For dogs, published doses vary. A single-blinded trial used levetiracetam at 30 mg/kg/day or 60 mg/kg/day divided into three daily doses [13]. A pharmacokinetic study used a mean dose of 26.4 mg/kg [2]. A 2024 study found that oral doses of 99 to 216 mg/kg/day were needed to reach a serum concentration of 20 micrograms per milliliter when levetiracetam was used alone or with phenobarbital [11]. These are research doses, not label doses, and they show why dosing has to be individualized.

Never adjust a pet's levetiracetam dose without veterinary guidance. The dose depends on the pet's weight, kidney function, other medications, and seizure pattern.

The Emergency Role of Injectable Levetiracetam

Status epilepticus is a medical emergency. It is a seizure that lasts long enough or repeats often enough that the brain cannot recover between events. Cluster seizures are a related emergency, where multiple seizures occur in a short period.

Injectable levetiracetam is used in these situations [3]. It is given intravenously in a hospital, often after or alongside a benzodiazepine, which is the first-line emergency drug. Levetiracetam's role in the emergency setting is to provide a longer-acting anticonvulsant once the immediate seizure is stopped.

Intranasal levetiracetam is an emerging option. A study in healthy dogs found that a compounded intranasal product reached target concentrations quickly and maintained them for several hours [9]. This route is not yet standard in general practice, but it is being investigated for early seizure control when intravenous access is not immediately available.

If a pet is in status epilepticus or having cluster seizures, this is an emergency. Call the veterinary hospital and go in. Do not wait to see if the seizure stops on its own.

Side Effects and What to Do About Them

Levetiracetam is generally well tolerated. In the 52-dog retrospective study, no dog was reported to have serious side effects [1]. In the 19-dog structural epilepsy case series, side effects were noted in 8 of 19 dogs but were considered mild in all cases [15].

The most common side effects reported in dogs and cats are sedation, lethargy, ataxia (wobbliness), and inappetence [7]. In the cat trial, lethargy, inappetence, and ataxia occurred at similar rates in the levetiracetam and phenobarbital groups, but the levetiracetam side effects were mild and transient while the phenobarbital side effects persisted [7].

Behavior changes are a recognized but underappreciated effect. A retrospective study of 84 dogs on levetiracetam found that about half had preexisting behavior changes before treatment, and some of those dogs worsened or developed new behaviors after starting the drug. About one quarter of dogs without preexisting behavior problems developed behavior changes associated with the medication [19]. These changes can include anxiety, agitation, or other shifts in temperament. They are rarely dangerous but can affect quality of life.

Kidney function matters for side effects. A retrospective study of 37 dogs with seizures compared dogs with preexisting chronic kidney disease to dogs without it. In the kidney disease group, 85 percent developed adverse effects compared with about 53 percent in the non-kidney disease group, and increases in blood urea nitrogen or serum creatinine were more common in the kidney disease group [4]. This is the strongest evidence that levetiracetam dose adjustment is needed in dogs with kidney impairment.

If a pet develops sedation, wobbliness, or behavior changes after starting levetiracetam, contact the veterinarian. Do not stop the drug abruptly. Sudden withdrawal of an anticonvulsant can trigger seizures.

A Table of Indication, Route, Monitoring, and Adverse Effects

Which Pets Should Not Receive Levetiracetam

Levetiracetam is not appropriate for every seizure patient. A veterinarian should evaluate the following before prescribing it.

Pets with kidney disease need caution. Because levetiracetam is cleared by the kidneys, dogs with chronic kidney disease developed adverse effects at a much higher rate than dogs with normal kidneys, and some had worsening kidney values after starting the drug [4]. Dose reduction or longer dosing intervals are needed, and kidney values should be monitored.

Pets with known hypersensitivity to levetiracetam should not receive it. This is a general principle for any medication.

Pets on phenobarbital need higher or more frequent levetiracetam dosing because phenobarbital lowers levetiracetam blood levels [11][10]. This is not a reason to avoid the drug, but it is a reason to monitor and adjust.

Pregnant or breeding pets should be discussed with a veterinarian. There is limited veterinary data on levetiracetam in pregnancy, and the decision should be individualized.

Pets with liver disease may actually be good candidates for levetiracetam because the drug has minimal liver metabolism [3]. This is one of the situations where levetiracetam has an advantage over phenobarbital.

Drug Interactions

Levetiracetam has fewer drug interactions than most anticonvulsants [3]. The main interaction in veterinary medicine is with phenobarbital.

Phenobarbital increases levetiracetam clearance. In healthy dogs, concurrent phenobarbital reduced levetiracetam peak concentration from about 32 micrograms per milliliter to about 18 micrograms per milliliter and shortened the half-life from about 3.4 hours to about 1.7 hours [10]. A study in dogs with epilepsy confirmed this and showed the effect is dose-dependent [11]. The practical result is that dogs on phenobarbital often need a higher levetiracetam dose or three-times-daily dosing instead of twice-daily.

Potassium bromide does not lower levetiracetam levels. In fact, dogs on levetiracetam plus bromide had significantly higher levetiracetam concentrations than dogs on levetiracetam plus phenobarbital [2].

Levetiracetam does not appear to significantly alter the levels of other antiseizure drugs, which is part of why it is a popular add-on [3]. This is different from phenobarbital, which affects many other drugs through liver enzymes.

Always tell the veterinarian about every medication, supplement, and compounded product the pet is receiving. This includes over-the-counter products and herbal supplements.

How Keppra Compares With Other Anticonvulsants

Phenobarbital is the most commonly prescribed first-line antiseizure drug in dogs in primary care [17][18]. It is effective and inexpensive, but it requires liver monitoring and can cause sedation, ataxia, and long-term liver changes. In a study comparing caregiver assessments of dogs on levetiracetam, zonisamide, or phenobarbital monotherapy, phenobarbital had the highest rate of reported adverse effects at 77 percent, compared with 39 percent for zonisamide. Levetiracetam fell between the two. Treatment failure rates were 51 percent for phenobarbital, 45 percent for zonisamide, and 35 percent for levetiracetam, but the differences were not statistically significant [14].

Potassium bromide is another older anticonvulsant, often used as an add-on. It has a long half-life and can cause sedation and hind limb weakness. It does not lower levetiracetam levels [2].

Zonisamide is a newer anticonvulsant used in dogs. In the caregiver survey, zonisamide had the lowest rate of reported adverse effects but a treatment failure rate of 45 percent [14].

Pregabalin has been studied as an add-on in dogs with drug-resistant epilepsy. In a prospective trial comparing pregabalin add-on to a levetiracetam dose increase, treatment success was low in both groups, with 2 of 14 dogs in the pregabalin group and 1 of 12 dogs in the levetiracetam group meeting success criteria [12]. This study suggests that simply increasing levetiracetam may not be enough for some drug-resistant dogs.

Levetiracetam's main advantages are its safety profile, minimal liver metabolism, and few drug interactions [3]. Its main disadvantage is that it is short-acting and often requires frequent dosing, and it is not always effective as monotherapy [13][14].

Monitoring a Pet on Keppra

Monitoring levetiracetam in pets involves several components.

Seizure diary. The most important monitoring tool is a record of seizure dates, durations, and patterns. This is how the veterinarian judges whether the drug is working. In the 52-dog study, treatment success was defined as a 50 percent or greater reduction in seizure frequency [1].

Serum levetiracetam concentration. This is not routinely measured in general practice, but it is available at referral centers and can guide dosing. A 2024 study found that oral doses of 99 to 216 mg/kg/day were needed to reach a serum concentration of 20 micrograms per milliliter, which is a target borrowed from human medicine [11]. The same study found that phenobarbital lowers levetiracetam concentrations in a dose-dependent way [11].

Kidney panel. Because levetiracetam is renally cleared, blood urea nitrogen and creatinine should be checked before starting the drug and periodically during treatment, especially in older pets or pets with known kidney disease [4].

Liver panel. Levetiracetam has minimal liver metabolism, so liver monitoring is less critical than with phenobarbital [3]. A baseline panel is still reasonable.

Side effect check. Owners should report sedation, wobbliness, appetite changes, or behavior changes. In the cat trial, side effects were mild and transient with levetiracetam [7]. In dogs, behavior changes occurred in a meaningful proportion of patients [19].

Recheck timing. A reasonable schedule is a recheck within the first few weeks after starting or adjusting the dose, then every three to six months once the pet is stable. The exact schedule depends on the pet's other medications and kidney function.

Questions to Ask a Veterinarian

Before starting levetiracetam, or when refilling a prescription, these questions help owners understand the plan.

1. Is levetiracetam being used as an add-on or as monotherapy for my pet?
2. What dose and how many times per day?
3. Should I use the regular or extended-release form?
4. Does my pet need a serum levetiracetam level checked?
5. When should kidney and liver values be rechecked?
6. What side effects should I watch for at home?
7. What should I do if my pet has a seizure while on this drug?
8. Is there a plan for emergency seizure control if my pet clusters?

Limitations and When to Contact a Veterinarian

This article is educational and cannot replace an examination by a veterinarian. Every pet's seizure disorder is different, and the right medication, dose, and monitoring plan depend on the individual patient.

Contact a veterinarian promptly if any of the following occur:

• A seizure lasts longer than a few minutes or does not stop.
• Two or more seizures occur within 24 hours (cluster seizures).
• The pet does not fully recover between seizures.
• New or worsening sedation, wobbliness, or weakness after starting levetiracetam.
• Loss of appetite lasting more than a day.
• Vomiting or diarrhea that does not resolve.
• Behavior changes that concern you, such as anxiety, agitation, or aggression.
• Signs of kidney problems, such as increased drinking and urination, or decreased appetite.
• Any seizure that seems different from the pet's usual pattern.
• The pet misses a dose or the owner is unsure about dosing.

Do not stop levetiracetam abruptly. Stopping an anticonvulsant suddenly can trigger seizures, including status epilepticus.

Frequently Asked Questions

What is Keppra used for in dogs and cats?

Keppra (levetiracetam) is an anticonvulsant used to reduce seizure frequency in dogs and cats. It is most often used as an add-on to other antiseizure drugs, and the injectable form is used in hospitals for emergency seizure control [1][3].

How does levetiracetam work?

Levetiracetam binds to a protein called SV2A, which is involved in how nerve cells release chemical messengers. This is different from how older antiseizure drugs work [3].

Is Keppra safe for dogs and cats?

Levetiracetam is generally well tolerated. The most common side effects are sedation, lethargy, ataxia, and inappetence, and these are usually mild [1][7][15]. Behavior changes have been reported in some dogs [19].

Does levetiracetam affect the liver?

Levetiracetam has minimal liver metabolism, which is one of its advantages over phenobarbital [3]. It is cleared by the kidneys instead.

Do pets with kidney disease need a different dose?

Yes. Dogs with chronic kidney disease developed adverse effects at a higher rate than dogs without kidney disease, and some had worsening kidney values after starting levetiracetam. Dose adjustment and monitoring are needed [4].

Can levetiracetam be used for status epilepticus?

Yes. The injectable form is used in hospitals for status epilepticus and cluster seizures [3]. Intranasal levetiracetam is being studied for rapid seizure control [9].

Does phenobarbital interact with levetiracetam?

Yes. Phenobarbital lowers levetiracetam blood levels and shortens its half-life, so dogs on both drugs often need a higher levetiracetam dose or more frequent dosing [11][10].

Can levetiracetam be used as the only seizure medication?

It can be, but evidence for monotherapy is mixed. Some dogs do well on levetiracetam alone, while others continue to have seizures and need a different or additional drug [13][14][15].

Related Articles

• Levetiracetam Keppra Dose: Emergency and Maintenance Dose Calculator
• Drug Interactions with Anticonvulsant Medications in Veterinary Patients: Phenobarbital, Potassium Bromide, and Levetiracetam
• Dog Arthritis Medication
• Dog Separation Anxiety Medication
• Is Your Dog's Medication Expired? Risks and What to Do
• Dog Hot Spot Treatment Medication

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